Means for centering tubular well strings



Aug. 19, 1941.

G. H. BRODIE 2,253,415

MEANS FOR CENTERING TUBULAR WELL STRINGS Filed Sept. 8, 1939 clam/M414.

` Patented Aug. 19, 194i y 2,253,41Q35H y MEANS Fon CENTERING. TUBUI-.AnWELL s'rmNGs y Gerson H. Brodie, Houston, Tex. Application september8,1939, serial Ne. 94,010 1s claims. (cl. 16e-1) This invention relatesto means. for centering tubular well strings.. such as a casing string,in a wellbore.

The primaryobject of the invention is to insure that the cement used inthe completion of the well encircles the casing completely, leaving noportion of either the wall of the bore or the casing uncovered bycement.

-A further object is to furnish means that will positively move thecasing away from any portion of the bore-hole wall, against which it maybe leaning due tothe crookness of the hole or for any other, cause.

A still further object is to supply means to perform the operation ofmoving the casing away from the bore-hole wall in a minimum of time,without resorting .to running drill pipe into the hole to accomplish thetask.

Another object is to provide means suiiiciently strong to be loweredinto a deep hole without being damaged, and which will effect sigalingthe successful completion of the operation of cementing by means of thepressure gauge normally used on the mud system in drilling oil wells.

With the foregoing objects outlined and with Fig. 7 is an elevation ofone of looking from the inner` side thereof.

Fig. 8 is a bottom plan view of one of the wedges.

Fig. 9 is a side elevation of one of the wedges.

the wedges Referring to the drawing, Ill designates the 4 wall of a wellhole in which a tubular well string.

such as a casing string Il. is inserted. In the string, I interpose, atsuitable points, centering other objects in view which will appear asthe description proceeds, the invention consists in the nov/e1 featureshereinafter described vin de.- tail, illustrated in the accompanyingdrawing, and more particularly pointed out in the appended claims. v

In the drawing: Fig. 1 is a vertical sectional view of a. portion of awell hole and showing my improved means arranged therein, such meansbeing shown partially in elevation and partially in vertical sectionandwith a pair ofcentering collars with their wedges extended. Fig. 2 is avertical sectional view partly in elev' tion of one of the centeringcollars shown inte ed in the casing string and with the wedges inetracted position.

F7155. 3 is a horizontal sectional view taken on line 3 2 of Fig.. 2. l

Fig. 4 is a vertical sectional view illustrating the manner in which theplug causes projectionA of the wedges of a centeringcollar. A l Fig. 5is a horizontal sectional view taken on the rune 5 5 of Fig. 4.

Fig. 6 is a perspective view of one ofthe i merle@ latches employed inholdin: af-wedge in vprojected 90811210- collars I2; two such collarsbeing shown in Fig. l.

As best shown in Fig. 2, each collar may consist of a section ofpipe I3havingan internal diameter substantially equal to the internal diameterof the casing sections I4, and provided at its ends with. internalthreads to engage' external threads on the 'casing sections as indicatedat I5.

As best illustrated in Figs. 3 and 5, the collar I2 is provided withvertically disposed slots I6 to accommodate or guide wedges orwedge-shaped centering elements I1.

The upper or small end of each wedge is hingedly connected by anysuitable means located at I8 to the collar I2, and the lower or largeend of each wedge is of arcuate shape as indicated at I9 so as to snuglyilt the lower end portion of the slot in which the wedge operates.

As it is necessary when the wedges are projected to seal the jointsbetween the wedges and the slots, the inner portion of each wedge isprovided with oppositely disposed beveled surfaces 20 to impinge againstbeveled surfaces 2| at the inner portions of the slots I8. In practicethe beveled section 20 of each wedge will be treated with vulcanizedrubber prior to introduction of the string into the well to insuresealing when the wedges are extended. `Such vulcanized rubber would beof gradually increasing thickness toward the lowermost part of thewedseilare. l

At the lower end of each wedge, a knurled latch 22 (Fig. 6)4 extendsinto the slot in which the web operates, and 'such latch'tlmctions tohold the wedge in projectedn position after it has been extended, in amanner hereinafter explained. Each latch has a resilient .shank 2l thatis secured to the exterior of the collar I2 by means of a screw 24 orthe` like.

Each wedge is provided with a semi-cylindrical shield 2l, secured tothevwedge by any suitable means. auch as screwsv 2l,l andsuch shieldscarry shear pins 21 which/extend intoihe eeuu u] allowed to float down Abottom,

' `From the foregoing.' it is invention may be readily (Fig. 3) andnormally hold the wedges inretracted position.

The wedges are expanded by any suitable means, 'such as the plug l28,shown in Figs. l, 4

and 5. Such plug is of substantially cylindrical form and has anellipsoidal nose 23 at its lower` end. Such nose'is constructed-of-steelor any other type of hard4 metal and the outside diameter of the plugapproachesthe inside diameter of the collar.

The plug is of tubular formation and provided thr ugh which-thedrillingmud and cement may at the proper time.

A sealing cup 36 is arranged at the top of the plug to insuremaintenance of pressure while.

the plug is forced downwardly through the casing string under thepressure of the pump. An abutment 31 attached to the stem 32 bewith theflow shoe 33 so as`to cause shearing of the pin 33 and opening of thevalve 3| when the plug 28 reaches the bottom of the casing string.

In operation, when it is desired to center a I string of casing in thewe ii hole, one or more of I2 are inserted in the the centering collarsstring at desired positions before the latter is 'inserted in the hole.When the string is made up, the plug 23 is -dropped intq the easing anduntil stopped bythe retracted wedges I1 of the uppermost centeringcollar. A drilling mud connection is made at the top of the string and apump pressure lower than that required to break the shearlpns 21V is lowthe shear pin 33 is adapted to cooperate applied. When the pump stops,it is certain .A

that wedges I1 are still closed, Pressure is then increased by the pumpuntil the breaking point .of the shear pins 21 is reached, at which'time the pumps move freely, inlicating passage of the plug -through thecentering collar. This procedure is repeated'as the-plug encounters the.several collars.

When the plug forces` appended shields .25 open, the knurled latches 22coact with the lower ends of the wedges and prevent the` return of thewedges to closed position.

When the plug 23 has been pumped to the the abutment 31 comes intoforcible contact with the noat shoe 38 with the result that the stem. 32is halted on its downward movement while the plug 23 shears the pin 331and continues downwardly .until it contacts such abutment. This causesopening of the valves 3| and 33 and permits the drilling mud and thecement to circulate freely through the plug, out of the casing and intothe drill hole. When circulation is thus freely obtained, the casing iscentered at the desired depths in the bore hole. believed that theconstruction, operation and advantages'o'f the uriderstood and I amaware that changes lmay be made in the' details disclosed withoutdeparting from the spirit of the invention. as expressedy in the claims.

What I claim and desire to secure by Letters the wedges and their i ladapted to open the assegni ing interposed therein normally retractedbut projectable elements adapted to be extended outwardlyfrom varioussides of the string and to engage the "wall of a bore hole for centeringthe string therein, a plug adapted to travel down the string andprovided with means for projecting said centering. elements, andlatching means cooperating with said elementsy for holding the same inprojected position.

2. In combination, atubuiar well string having interposed thereinnormally retracted but projectable wedges, adapted to be extendedoutwardly from various sides of the string and to engage the wall of abore hole for centering the string therein. each wedge having itssmaller end at the top thereof, a plug adapted to travel down the stringand provided with means for engaging said wedges and projecting the sameoutwardly as theplug travels downwardly, and latching means arranged atthe lower end of Jeach wedge for holding the same in projected position.

3. In combination, a tubular well string provided with slots at varioussides thereof, normally retracted but projectable elements arranged t`ooperate in said slots and to engage the wail of a` bore hole forcentering the string therein, and a plug adapted to travel down `thestring and provided with means for projecting said centering elements,the well string and elethe string and provided with means for project-4ing s'aid centering elements, a shield united with each element, andfragible means for securing the shields to the well string.

5. In combination, a tubular 'well string having interposed thereinnormally retracted but proj ectabie elements adapted to extendedoutwardly from various sides of e string ,and to engage the wall of abore hole for centering the string therein, a normally closed valve atthe bottom of 4the string, and a valved plug adapted to travel down thestringand provided with means for projecting said centering elements andfor opening said valve.

6. In combination, a tubular well string having a normally closed vaiveat the lower end thereof and provided with interposed normally retractedbut projectable elements adapted to be extended outwardly from varioussides of the string and to engage the wall of a bore hole for centeringthe string therein, a tubular plug adapted to travel down the string andprovided with means for projecting said centering elements said plugtherethrough, a Isecond valve adapted to close said passageway andprovided with a depending stem which extends through the plug and isfirst-mentioned valve.

'7.In combination, a tubular well string having a normally` closed valveat the lower end thereof and provided with interposed normally retractedbut projectabie elements adapted to be extended outwardly from varioussides of the string and to engage e wall of a bore hole for 1.Imcombination. a tubular well' string hav- 75 centering the stringthesei\n, a 'plug having a passageway extending Vadapted tocpen thefirst-mentioned valve, and

frangible means for normally holding the stem in such position as toclose said second valve.

8. In combination, a tubular well string having interposed thereinnormally retracted but projectable elements adapted to be extendedoutwardly from various sides of the string and to engage the wall of vabore hole'for centering the string therein, a normally closed valveassociated with .the well string and arranged below said elements, andvalved means adapted to travel down the string, to project saidcentering elements and open said valve. 9. A method of centering andcementing oil well casing comprising forcing a plug down the casing andutilizing such plug to project centering'elements' from the casing andto open a discharge valve of the casing, and then forcing cement throughsaid plug and valve into the bore hole in which the casing is centered.-

10. A centralizing device'for well casing and the like, comprising ahollow body secured to said casing, longitudinally restrained radiallyextensible members positioned in said body intermediate its ends, meansfor holding said members in a -retracted position in said body to besubstantially ilush with its outer surface, rigid means adapted to beintroduced into said body to ll the bore thereof to release said holdingmeans and positively extend said members radially from said body, andmeans associated with said extensible members to retain them in anextended position independently of said rigid means.

11. A centralizing device for well casing and the like, comprising ahollow body adapted to be secured to said casing, longitudinallyrestrained radially extensible members movably positioned in said body,means for holding said members in a retracted position in said body,said extensible members and said holding means adapted to be actuated bymeans operable from the top of said casing to release said holding meansand positively ext-end said members from said body, and means associatedwith said extensible members for holding them in their expanded positionindependently of the surface operable means.

12. A centralizing device for well casing and the like, comprising ahollow body adapted to be secured to said casing, a pluralitybflongitudinal slots circumferentially spaced in said body, a1ongitudinally tapered foot in each of said slots, means at one end ofsaid slots for retaining, said feet against inward or outward motiontherein, the wider ends of said feet adapted to be displaced outwardlyfrom said body by a rigid object introduced therein, and meansassociated with' said feet for holding them in their expanded positionindependently of said rigid object.

13. A centralizing device for well casing and the like, comprising atubular body member adapted to be connected to a well string,longitudinal slots in said body member, a longitudinally restrainedradially extensible element positioned in each of said slots, andholding means for nor'- mally holding said elements in retractedposition, said holding means being releasable by a'rigid objectintroduced into the body member to move said element outwardly from saidbody member.

14. A centralizing device for well casing and the like, comprising atubular body'member'ada'pted to be connected to a well string,longitudinal slots 15. In combination, a tubular well string hav.4

ing interposed therein normally retracted` but projectable elementsadapted to extend outward- 1y from various sides of the string, and a.valved plug adapted to travel down the string, said plug being adaptedto cooperate with said projectable elements to extend the same outwardlyinto contact with the wall of a bore hole for centering the stringtherein.

16. In combination, a tubular well string havin g interposed thereinnormally retracted but projectable elements adapted to extend outwardlyfrom various sides of the string, and a ported plug provided with anobturating member, said plug being adapted to cooperate with saidprojectable elements to extend the same outwardly into contact with thewall of a bore hole for centering the string therein.

GERsoN H. BRoDrE.

CERTIFICATE oF CORRECTION.V

Patent No. 2,255,ll.l5. August 19, 19111.

` GERsoN H. B RoDIE.

-It is hereby certified thaterror appears in me printed specification o"the above: numbered patent requiringcorrection ne follows: -Page 5,second-column, line 12, beginning with "15. A centralizing" strike outall to and lincluding 'the wordend period "memben" in line 2l,comprisingcl-aixn 15, and for the elaime now appearing as 11i, 15, and16, read 15, lh, and

15 respeetively; and that the said Letters.Patent shou1dbe read withthis correction therein that the same may conform to the record ofthe,case in the Patent office.

Signed andeealed this 50th day of September, A. D. 19111.

. Henry Van Arsdale, (Seal). A'cting Commissioner of Patents.

